I recieved my 8700c today and have been dinking around with it. One of the first things I tried was putting my fully charged 7100 battery in the 8700. They look about the same except the 8700's (C-S2) has squared edges.

From the top

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I read somewhere that non-blackberry batteries will not work anymore. It appears that even non-8700 blackberry batteries won't work.

I heard that the 8700 series battery has somesort of security feature in it that the blackberry looks for. The 7100 series batteries don't have these so they will not work in the 8700 series. I also heard that RIM would introduce this to all forthcoming batteries. This was told to me by the agent who sold me my 8700r who said that info was given to him by his RIM rep.

Has anyone definitively detemined whether a 7100 battery is OK to use in an 8700? I have checked this thread and the answer is not clear. Some people say no, but the following link advertises the same battery for both models:

Has anyone definitively detemined whether a 7100 battery is OK to use in an 8700? I have checked this thread and the answer is not clear. Some people say no, but the following link advertises the same battery for both models:

The ad is for a C-S2. I have an unused C-S1. Anyone know what the difference is?

I can answer the first half of your question, my wife has a 7100t and I have the 8700c, plus I ordered two more batteries from rim C-S2 with the lock symbol and all 4 work in my 8700 and her 7100, I got the stand alone desktop charger too, works great

The 7100i comes with a CS-2 battery, but does not have the lock symbol next to it. Also I do not have a 8700c here to test out the batteries. I assume the "lock batteries" you buy will work with all BB's, since I assume they are not assigned to specific device. No sense making a specific battery like that if you cant sell it.

pink

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I just got the 8700c and the battery life is terrible. What can I do, I've tried adjusting the backlight to the min setting but still end up with 2 bars by late afternoon.

I followed the charge to a T and I have horrible life too. About 1 day with 2 hours talk and no emails or text.... Very bad.. Did I get a bad battery? Whats the secret on charging and when you get a brand new battery, what did you guys do to it? Lithiums shouldnt have a memory from what I know, so whats the problem? Thanks.